Conventionally, as methods of the production of a highly durable packing material for liquid chromatography, a method which comprises impregnating a silica gel surface with polysilazane such as perhydroxypolysilazane, then baking this silica gel to form ceramic coatings on its surface to coating with ceramics, and chemically bonding a silane compound as a modification agent thereto (see, Patent Document 1), a method which comprises polymerizing a silicone compound having a hydrosilyl group on a silica gel surface to form a silicone polymer (see, Patent Document 2), and a method in which monofunctional silane having a steric protection group such as octadecyldi-t-butylchlorosilane or octyldiisopropyl chlorosilane in its structure is used as a silane compound to be a modification agent (Patent Document 3) were proposed.
However, any of the coating with ceramics in Patent Document 1, and the coating with a polymer in Patent Document 2 may possibly deteriorate the characteristics of the silica gel, while the steric protection group in Patent Document 3 may greatly change the selectivity of as a packing material for liquid chromatography.    Patent Document 1: JP-A-H10-206407.    Patent Document 2: JP-A-2003-149219.    Patent Document 3: JP-A-S63-137750.